Genetic counseling: Cleft Lip - Isolated, Unilateral, Incomplete
Cleft Lip - Isolated, Unilateral, Incomplete Contracting *Acknowledge previous contact *What were you hoping to gain from today's session? *What concerns and questions do you have? *Outline session agenda *Interim history *Dr. will examine to rule out possible syndromes associated with CL *We aren't expecting Dr. to find anything that makes him suspicious. Medical History Family History *Have you found out anything new about the family history? *Any new births, deaths, or diagnoses? Cleft lip and palate *Before genetic counseling can be given, numerous syndromes must be excluded. *Definition: CL/CP due to a failure of the union of the frontonasal process of the face with the lateral maxillary prominence at about 3-4 weeks post conception (35 days gestation) *Classification of clefts *Nonsyndromic vs. syndromic *80% are unilateral, 20% bilateral, extends to the palate in 70% of unilateral cases and 85% of bilateral cases *Incomplete or complete (involving the lip and the anterior maxilla vs. involving the lip, anterior maxilla, hard and soft palate) *Unilateral clefting commonly occurs on the left (2x more frequently than right) *Male to female ratio is 2:1 Incidence *CL +/- CP occurs in 1:1000 Caucasian births, 1.7:1000 Asian births and 1:2500 AA *Isolated cleft lip and palate account for 25% of the cases of clefting *Left unilateral clefts, right unilateral clefts, and bilateral clefts occur at a 6:3:1 ratio. Inheritance and Recurrence Risks *Most isolated occurrences are inherited multifactorially *Background risk: 0.1% (Harper) *RR- 3-7%, empiric *2-4% risk for offspring of an affected parent *2nd degree relative: 0.6% risk (Harper) Risks *Specific factors increase the risk for CL/CP **Severity of the trait (unilateral vs. bilateral; complete vs. incomplete) **Number of affected relatives **Sex affected (whether the person is of the sex opposite the most often affected) **How closely the individual is related to the affected person) Multifactorial Inheritance and Genetic counseling *A condition that is caused by several genes and the environment *Threshold model- baby inherits genes from both parents that increase the risk for cl/cp, then in combination with certain environmental factors the risk goes beyond the threshold level and the baby develops a cleft *Although there are multiple genes involved 3 predisposing genes have been identified. **Explaining this to parents: ***Children with cl/cp inherit genes in a random way from their parents ***Parents cannot control which genes they pass on ***Some of these genes contribute to facial development. We know that there are over 100 genes that contribute to the development of the lip and palate; there have been 3 genes found that we call predisposing genes- which means that in animal models we have been able to show that disruption or changes in this gene can lead to clefting. ***when the lip forms in early development, cells migrate together to close the lip ***Multiple genes tell those cells to move the way that they are suppose to ***It takes more than genetic factors for someone to develop a cleft ***Environmental factors play a big role. ***We know some of the factors that interact with genes to cause clefts (smoking, alcohol, some medications) but we don't know them all. ***There are some protective factors- folic acid ***Timing is important, the lip is completely closed by the 35th day of gestational development (medicine or other factors after this time wouldn't have an effect on the lip) *Reassurance: you did everything within your control to have a healthy baby. Even if risk factors were present (smoking, drinking etc) the mother should be reassured that even without these factors the baby could have been born with a cleft. *Currently there is no way to guarantee that a baby isn't born with a cleft. The best thing to do in future pregnancies is to avoid smoking, drinking, and certain medications (anticonvulsants, retinoic acid), and to take folic acid periconceptionally. What's next? *Feeding issues? Make sure the baby is getting enough nutrition. Infants with isolated cleft lip (without cleft palate) seldom have problems feeding by breast or bottle. *Surgery: objective- to close the lip to create a pleasing face that will develop normally with minimal scarring. *Closure is performed when the baby is approximately 3 months old at weighs at least 10 pounds. *Correction of the nasal deformity is usually performed at the time of the lip repair. *Additional surgeries will be necessary to enhance the appearance of the lip and/or nose. *Initial surgery lasts ~2-3 hours and the hospital stay is usually 2-4 days. **During this time special considerations are necessary for feeding and positioning. Elbows are restrained from bending. Positioning the child in an infant seat prevents rolling over and injuring the lip/nose. No pacifiers or nipples allowed. Fed with a special syringe feeder with a soft tube. It takes about 3 weeks for the wound to heal enough to stop these special precautions. **The lip scar is initially red and swollen, but begins to mature and improve in appearance in ~6 months. *Isolated cleft lip- no expected problems with hearing or speech. *Possible problems with teeth…there can be missing or crooked teeth in the area of the cleft. Follow up *Pediatrician for routine care *Contact craniofacial team- referral made, scheduled for the Nov. infant/toddler meeting- letter has been sent. *help with feeding, special bottles, positioning of the baby *The craniofacial team has a psychologist that can help with the emotional concerns of having a child with a facial cleft. Interested in scheduling an appointment? *Follow up with Dr. Billmier *and Dental services? References *Smith's *Practical Genetic Counseling *Emery and Rimoin *Bender PL. Genetics of Cleft Lip and Palate. (2000). Journal of Pediatric Nursing. 15:4. *Clefts of the Lip and Palate. 1997. Tennessee Craniofacial Center. Notes The information in this outline was last updated in 2002. Material obtained under GFDL Licence from http://en.wikibooks.org/wiki/Handbook_of_Genetic_Counseling